Thin, elongated, tubular structures on the surface of bacteria that help them to attach to other bacteria and solid surfaces.

Explanation

To answer the question regarding the thin, elongated, tubular structures on the surface of bacteria that assist in their attachment to other bacteria and solid surfaces, we can break down the solution into the following steps:

### Step-by-Step Solution:

1. **Identify the Structures**: The question refers to specific structures found on the surface of bacteria. The two main types of structures that fit this description are pili and fimbriae.

2. **Define Pili**: Pili are thin, elongated, tubular structures that are present on the surface of bacteria. They play a significant role in the attachment of bacteria to solid surfaces and host tissues.

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